1. Field of the Invention
The invention relates generally to microwave systems and, more particularly, to high-speed front-end shutter components.
2. Description of the Related Art
Microwave systems have become increasingly important to electronic systems in many different fields, including defense applications. Modern military platforms are highly dependent on microwave systems for their on-board communications, radar and electronic warfare systems. The ability to protect these systems from high energy threats, such as high power microwave (HPM) weapons, directed energy weapons, or electromagnetic pulses (EMPs) that arise from nuclear blasts, is paramount to the effectiveness of the military.
Microwave receiver front-ends typically include a high-sensitivity low-noise amplifier (LNA) which is particularly vulnerable to high energy exposure. Receiver front-ends are, by functional necessity, well-coupled to electromagnetic energy from the environment via an antenna. As a result, the receiver front-end components (i.e. the entire RF to IF chain) are vulnerable to semiconductor junction breakdown, arcing, thermal damage and electromigration-induced damage that may accompany a high energy electromagnetic attack. Therefore, receiver front-end systems require power limiters to isolate the vulnerable components during a high power electromagnetic attack.
The current state of the art falls roughly into two categories; solid state diode limiters or plasma discharge limiters. Solid state emitter devices provide fast response (˜1 ps); however they can only handle a maximum peak power of approximately 100 kW and typically handle only 10 W to 100 W over the duration of a 1 ms HPM attack. Plasma discharge tubes provide protection against significantly larger power levels but suffer from slower switching times. Present state of the art power limiters for microwave receiver front-ends do not sufficiently protect against the extraordinarily high electric fields generated by EMPs, HPM, or directed energy weapons. Hence, there is a need for a capable power limiter solution.